Splinter-guards of explosively actuated power tools



Oct. 26, 1965 c, RQSSELET 3,214,073

SPLINTER-GUARDS OF EXPLOSIVELY ACTUATED POWER TOOLS Filed Nov. 19, 19623 Sheets-Sheet 1 In venfor CLAUDE ROSfiELET 0a. 26, 19.65 RQS LET3,214,073

SPLINTER-GUARDS OF EXPLOSIVELY ACTUATED POWER TOOLS Filed Nov; 19, 1962s Sheets-Sheet 2 In van for 3 c cmupe 180551157 5 m im Oct. 26, 1965 c.ROSSELET 3,214,073

7 SPLIN'IER-GUARDS OF EXPLOSIVELY ACTUATED POWER TOOLS Filed Nov. 19,1962 s Shets-Sheet 3 INVENTOR cm 1105 ROSSELET pV MmA /W ATTORNEYSUnited States Patent 3,214,073 SPLINTER-GUARDS 0F EXPLOSIVELY ACTUATEDPOWER TOOLS Claude Rosselet, Founex, near Nyon, Switzerland, assignor toSarmi S.A. Societe dApplications de Recherches Minieres etIndustrielles, Lenzerheide, Grisons, Switzerland, a Swiss company FiledNov. 19, 1962, Ser. No. 238,382 Claims priority, applicationSwitzerland, Nov. 23, 1961, 13,659/61 7 Claims. (Cl. 227-11) The presentinvention relates to the splinter-guards which are intended to beemployed on explosively actuated power tools known as sealing guns, thatis to say devices which are used for driving fastening articles such aspins into hard and compact materials such as cement, concrete or woodunder the action of an explosive charge.

More particularly, the invention relates to eccentrically movablesplinter-guards which can be brought manually into an eccentric positionand which are fitted, on the one hand, with elastic restoring meansallowing the splinter-guard to be moved from the normal centeredposition into said eccentric position and, on the other hand, withlocking means for temporarily maintaining the splinterguard in saideccentric position despite the force of the elastic restoring means whensaid means have been brought under tension as a result of the eccentricpositioning operation.

The present invention has for its object to provide, when thesplinter-guard has been brought to the eccentric position by theoperator, for the automatic return of said splinter-guard into thenormal position, when the tool is fired, said automatic return being theresult of the firing action.

Preferably, maintaining the splinter-guard in the eccentric positionwould be possible only by the use of a detachable safety means.

Thus, according to the invention, an eccentrically movablesplinter-guard with elastic restoring means which tend to bring back andmaintain the eccentrically movable portion of the splinter-guard in thenormal centered position with respect to the tired portion (which ismounted on the tool) of said splinter-guard, and comprising lockingmeans which are able to be manually operated, is characterized in thatsaid locking means are adapted to be responsive to the firing action, sothat, on the one hand, the eccentrically movable portion of thesplinterguard which is brought manually into the off-center position islocked in this position in opposition to the elastic restoring meansand, on the other hand, said locking means are capable of returningthemselves, under the firing action, into the unlocked position in whichthe said eccentrically movable portion returns to the centered positionunder the action of the restoring means.

Further particular features and characteristics of the invention will bebrought out by the description which follows below of one example ofconstruction of the new improved splinter-guard, said example beingdiagrammatically illustrated in the accompanying drawings, in which:

FIG. 1 :is a view at large scale and in cross-section parallel to thepivotal axis of the eccentrically movable portion of the splinter-guardshowing the manually operated locking means in the position in which amanual control unit is locked by the safety means;

FIG. 2 is a view in cross-section taken along the line II-lI of FIG. 1;

FIG. 3 is a view similar to FIG. 1, the locking means having beenreleased by the safety means;

FIG. 4 is a view in cross-section taken along the line IVIV of FIG. 3; e

3,214,073 Patented Oct. 26, 1965 FIG. 5 is a plan view (from the rear),at a reduced scale, of the complete splinter-guard unit in the normalcentered position;

FIG. 6 is a plan view similar to FIG. 5, showing the splinter-guard inthe eccentric position;

FIG. 7 is a view in cross-section taken along the line VIIVII of FIG. 5,showing the splinter-guard mounted on the front part of an explosivelyactuated power tool.

FIG. 8, lastly, is a developed view, in cross-section along the lineVIIIVIII of FIG. 6, showing the return spring arrangement of thesplinter-guard.

In the embodiment shown in the drawings, the reference 1 designates afixed part of the splinter-guard, said fixed part being off-center withrespect to a sleeve 2 and integral with said sleeve. The sleeve 2comprises two sleeve members 2a and 2b and serves for the purpose ofmounting the splinter-guard on the forward tool part A and is co-axialwith the tool barrel B. The eccentrically movable part 3 of thesplinter-guard is adapted to pivot on the part 1 about a finger 18(located on the center x) of said part 1, said finger 18 engaging a hole20 of the movable part 3. In an arcuate recess 19 of the part 1 ishoused a return spring 16 which is in abutment against an end wall 19aof said recess 19 and against a stop member 17 integral with the part 3,and which tends to bring back said eccentrically movable part 3 into thenormal position shown in FIG. 5. In order to allow an easy handling orbearing of the tool together with the splinter-guard, the sleeve member2a is surrounded by a rubber grip P.

The fixed part 1 of the splinter-guard carries a box 4 inside which areformed two cylindrical chambers 5 and 9having their axes at right anglesto each other and opening into each other to a small extent. The axis ofthe chamber 5 being parallel to that of the sleeve 2. Inside thecylindrical chamber 5 can slide a piston 6 which forms a locking memberand the front part of which is capable of passing freely an opening 7which is bored in the part 1 and is in register with the chamber 5. Theeccentrically movable part 3 of the splinter-guard is provided with afrusto-conical hole 8 which, when the part 3 is located in theelf-center position shown in FIG. 6 accordingly moves to come inregister with the opening 7. The front end of the piston 6 terminates ina frustoconical portion 6a having a shape which corresponds to that ofthe hole 8. The piston 6 additionally comprises a circular groove 6b andthe rear end thereof terminates in a tail-piece 60 which projects fromthe box 4.

There is located, inside the chamber 9, a barrel or drum 10 which isadapted to rotate and to slide axially inside said chamber and which isnormally thrust forwards by a restoring spring 11 bearing on the base 12of a stem 13 which is intended to receive the bored rod of a safety keyC. There is additionally provided inside the chamber 9 an obliqueseating, or rib, 9a which is intended to maintain the drum 10 in awell-defined angular position, said diagonal seating being designed tocooperate, when the drum is in the forward position, with acorresponding oblique groove 10c cut in said drum.

The drum 10 is provided, in addition to the axial bore into which thekey is intended to be fitted, with a recess 10a for the key web. In thenormal condition (that is to say when the key is withdrawn), the drum 10projects inside the chamber 5 and accordingly penetrates inside thegroove 6b of the piston 6, thereby locking said piston axially in theposition shown in FIGS. 1 and 2. In this position, a locking between theparts 1 and 3, when the latter has been brought in the eccenteredposition, is made impossible.

A flat portion 10b is also milled in the drum 10 and permits the slidingmovement of the piston 6 when said drum has been brought, by means ofthe key, into the position shown in FIGS. 3 and 4.

Finally, there has been formed in the front wall 15 which closes thechamber 9 a keyhole which is suitably orientated in order to ensure thatwhen the key is withdrawn, the drum is necessarily located in theposition shown in FIGS. 1 and 2 (piston 6 locked in inoperativeposition).

The splinter-guard which has just been described operates as follows:

When there is no key present, the drum is accordingly immobilized in theaxial and angular positions represented in FIGS. 1 and 2, wherein thehollowed-out portion of said drum is engaged with the diagonal seating9a under the action of the spring 11, whereas the piston 6 is locked inits top position. The operator is always able, as a result of a manualoperation, to bring the part 3 of the splinter-guard into the off-centerposition shown in FIG. 6, but, as soon as it is released, said partreturns, under the action of the spring 16, into the normal positionshown in FIG. 5.

In order to lock the part 3 of the splinter-guard in the otf-centerposition, it is necessary to push axially the drum 10 by means of thekey C (and in opposition to the thrust applied by the spring 11) and tocause said drum to rotate, again by means of said key, through an angleof approximately 90, so as to bring said drum into the positionrepresented in FIGS. 3 and 4. At this moment, after having brought thepart 3 of the splinterguard into the off-center position, the operatorcan press on the tailpiece 6c of the piston 6 so as to thrust thislatter downwards and engage its frusto-conical part 6a inside thestriking-plate hole 8 of the eccentrically movable part 3 of thesplinter-guard said part 6a being jammed in the hole 8 under the actionof the torque developed by the return spring 16 on the movable part 3with respect to the fixed part 1. At this moment, the elements of thesplinter-guard take up the position which is represented in FIG. 6. ThisFIG. 6 and FIG. 8 show the spring 16 in its compressed state.

However, at the time of firing, due to the recoil phenomenon, togetherwith the shaking, or rattling, of the different parts of thesplinter-guard, the forward end 6a of the piston 6 is no longer jammedin the hole 8, so that the spring 11 moves back said piston. The resultis that the eccentrically movable part 3 of the splinterguard returnsimmediately into the centered position shown in full lines in FIG. 5. Itis to be noted that the automatic release of the piston 6 is improved bythe frusto-conical shape of the forward end 6a of said piston and thecorresponding shape of the hole 8, although said frusto-conical shape isnot essential.

Each time the part 3 of the splinter-guard is locked in the elf-centerposition, the piston 6 must be driven downwards, which is possible onlyinsofar as the safety key remains engaged inside the drum and is in theunlocking position (as shown in FIG. 3).

As soon as the key is withdrawn, the drum 10 is automatically broughtback and maintained in the locking position shown in FIGS. 1 and 2,thereby making it impossible to maintain automatically the part 3 of thesplinter-guard in the off-center position.

It is thus ensured that the operator cannot use the splinter-guard,either as a result of inadvertence, negligence or laziness, in theofi-center position thereof. The key can be in the care of a responsibleperson in charge who relinquishes possession of it in order to entrustit to the operator only with a view to permitting the execution ofspecial operations. Such special operations can neverthless be carriedout even in the event of loss of the key, but it is then necessary forthe operator to exert an effort in order to maintain the splinter-guardin the off-center position while firing and to overcome the force of thereturn spring 16, which is always loaded, as a result of the eccentricpositioning operation.

It is obvious that the example of embodiment of the new improvedsplinter-guard which has been described in the foregoing and asillustrated in the accompanying drawings has been given solely by way ofindication and not in any limitative sense and that any detailmodification can be made therein.

What I claim is:

1. In a splinter-guard for explosively actuated power tool, of the typecomprising a fixed part intended to be mounted on said tool, a movablepart which is rotatably coupled to said fixed part in such manner as tobe capable of displacement off-center with respect to said fixed partabout an eccentric motion axis, a return spring coupled to said fixedpart and to said movable part so as to bring back and maintain theeccentrically movable part in a centered position with respect to saidfixed part, the provision of: a box integral with said fixed part andprovided, on the one hand, with a first cylindrical chamber parallel tothe eccentric motion axis and, on the other hand, with a secondcylindrical chamber having an axis at right angles to the firstcylindrical chamber and intersecting said first chamber and furtherprovided, at one end thereof, with a stop-catch; a piston adapted toslide in said first chamber and having a circular groove formedsubstantially at the level of the second chamber, and that end of saidpiston which is directed towards the movable part of the splinter-guardin which is formed a frusto-conical hole being designed to terminate ina frusto-conical portion intended to penetrate into said hole for thepurpose of angularly locking the movable part with respect to the fixedpart of the splinter-guard; a cylindrical drum, rotatable inside thesecond housing, capable of carrying out therein an axial movement,provided on that side turned towards the stop-catch with engagementmeans adapted to come into engagement with said stop-catch, designed toreceive a control key, engaged under normal conditions with the grooveof the piston so as to immobilize said piston, and provided laterallywith a flat portion which, when said drum has been moved into a suitableposition by means of said key, permits the free movement of said piston;and a restoring spring located inside the second chamber for thrustingback the drum axially and bringing the engagement means of said druminto engagement with the stop-catch, so as to secure said drum againstrotation in a position in which the piston is thereby immobilized in theinoperative position.

2. In a splinter-guard for explosively actuated power tool, of the typecomprising a fixed part intended to be mounted on said tool, a movablepart rotatably coupled to said fixed part in such manner as to becapable of eccentric movement with respect to said fixed part about aneccentric-motion axis, return spring coupled to said fixed part and tosaid movable part so as to bring back and maintain the eccentricallymovable part in a centered position with respect to said fixed part, andmanually operable locking means, for locking, into the oif-centerposition, the eccentrically movable part of the splinterguard when thelatter has been brought manually into said position, in opposition tothe return spring, said locking means comprising: a box secured to saidfixed part and having therein a cylindrical chamber open at both endsand the axis of which is parallel to the axis of motion of said movablepart; a piston located in said chamber for sliding therein and having arear end and a front part both protruding from said chamber; hole meansprovided in the movable part, so located as to register with the axis ofsaid chamber, when the movable part has been brought in said eccentricposition, and adapted for receiving the front part of said piston when athrust is exerted on the protruding rear part of said piston.

3. A splinter-guard as claimed in claim 2 in which the front part of thepiston has a frusto conical forward end whereas the hole means has afrusto conical shape correspinding to the shape of said forward end.

4. A splinter-guard as claimed in claim 2, further comprising a safetymeans coupled to said box and so adapted that said piston can beactuated by hand only when said safety means is, in turn, actuated by aremovable control means.

5. A splinter-guard as claimed in claim 4, in which the safety meansconsists of a lock adapted to be capable of releasing the piston, whilethe removable control means consists of a key adapted to actuate saidsafety means.

6. A splinter-guard as claimed in claim 2, in which the piston isprovided laterally with a hollowed-out portion and the box is provided,in addition to the chamber for the movable piston, with a secondcylindrical chamber having its axis perpendicular to the axis of thepiston chamber and which intersects the said piston chamber, saidsplinter-guard additionally comprising a cylindrical drum inside saidsecond chamber and adapted to be rotated by a removable control andsafety key, said drum, which is normally engaged in the hollowed-outportion of said piston for the purpose of locking said piston in itsinoperative position, being provided laterally with a fiat portionwhich, when said drum is brought into a suitable angular position bymeans of said key, permits the free movement of said piston.

7. A splinter-guard as claimed in claim 6, in which the rotatable drumis provided, at one end thereof, with engagement means and is furtheradapted to slide axially inside the second chamber of which one end isfitted with engagement means which are complementary to those of thedrum, while said second chamber further comprises a restoring springwhich is disposed inside said second chamber for thrusting back the drumaxially and to cause the engagement means of the drum to be brought intoengagement with those of said second chamber, in opposition to thethrust which can be applied to said drum by means of the key, in orderto disengage said drum.

References Cited by the Examiner UNITED STATES PATENTS 2,700,764 2/55Catlin et a1. 144.5 2,869,127 1/59 Williams 144.5 X 2,952,020 9/60Schulz l44.5 3,060,438 10/62 Elliott 144.5

FOREIGN PATENTS 615,276 2/61 Canada.

GRANVILLE Y. CUSTER, 111., Primary Examiner.

1. IN A SPLINTER-GUARD FOR EXPLOSIVELY ACTUATED POWER TOOL, OF THE TYPECOMPRISING A FIXED PART INTENDED TO BE MOUNTED ON SAID TOOL, A MOVABLEPART WHICH IS ROTATABLY COUPLED TO SAID FIXED PART IN SUCH MANNER AS TOBE CAPABLE OF DISPLACEMENT OFF-CENTER WITH RESPECT TO SAID FIXED PARTABOUT AN ECCENTRIC MOTION AXIS, A RETURN SPRING COUPLED TO SAID FIXEDPART AND TO SAID MOVABLE PART SO AS TO BRING BACK AND MAINTAIN THEECCENTRICALLY MOVABLE PART IN A CENTERED POSITION WITH RESPECT TO SAIDFIXED PART, THE PROVISION OF: A BOX INTEGRAL WITH SAID FIXED PART ANDPROVIDED, ON THE ONE HAND, WITH A FIRST CYLINDRICAL CHAMBER PARALLEL TOTHE ECCENTRIC MOTION AXIS AND, ON THE OTHER HAND, WITH A SECONDCYLINDRICAL CHAMBER HAVING AN AXIS AT RIGHT ANGLES TO THE FIRSTCYLINDRICAL CHAMBER AND INTERSECTING SAID FIRST CHAMBER AND FURTHERPROVIDED, AT ONE END THEREOF, WITH A STOP-CATCH; A PISTON ADAPTED TOSLIDE IN SAID FIRST CHAMBER AND HAVING A CIRCULAR GROOVE FORMEDSUBSTANTIALLY AT THE LEVEL OF THE SECOND CHAMBER, AND THAT END OF SAIDPISTON WHICH IS DIRECTED TOWARDS THE MOVABLE PART OF THE SPLINTER-GUARDIN WHICH IS FORMED A FRUSTO-CONICAL HOLE BEING DESIGNED TO TERMINATE INA FRUSTO-CONICAL PORTION INTENDED TO PENETRATE INTO SAID HOLE FOR THEPURPOSE OF ANGULARLY LOCKING THE MOVABLE PART WITH RESPECT TO THE FIXEDPART OF THE SPLINTER-GUARD; A CYLINDRICAL DRUM, ROTATABLE INSIDE THESECOND HOUSING, CAPABLE OF CARRYING OUT THEREIN AN AXIAL MOVEMENT,PROVIDED ON THAT SIDE TURNED TOWARDS THE STOP-CATCH WITH ENGAGEMENTMEANS ADAPTED TO COME INTO ENGAGEMENT WITH SAID STOP-CATCH, DESIGNED TORECEIVE A CONTROL KEY, ENGAGED UNDER NORMAL CONDITIONS WITH THE GROOVEOF THE PISTON SO AS TO IMMOBILIZE SAID PISTON, AND PROVIDED LATERALLYWITH A FLAT PORTION WHICH, WHEN SAID DRUM HAS BEEN MOVED INTO A SUITABLEPOSITION BY MEANS OF SAID KEY, PERMITS THE FREE MOVEMENT OF SAID PISTON;AND A RESTORING SPRING LOCATED INSIDE THE SECOND CHAMBER FOR THRUSTINGBACK THE DRUM AXIALLY AND BRINGING THE ENGAGEMENT MEANS OF SAID DRUMINTO ENGAGEMENT WITH THE STOP-CATCH, SO AS TO SECURE SAID DRUM AGAINSTROTATION IN A POSITION IN WHICH THE PISTON IS THEREBY IMMOBILIZED IN THEINOPERATIVE POSITION.